Apparatus for measuring humidity conditions in materials



May 13, 1958 c. E. OHLHEISER 2,834,201

APPARATUS FOR MEASURING HUMIDITY CONDITIONS IN MATERIALS Original FiledNov. 3, 1948 2 Sheets-Sheet 1 CONSTANT PR sssz/ns A/R- LINE INVENTOR@MZKOM 06 dM/u, BY

6 A rro/r/vs Y y 13, 1958 c. E. OHLHEISER APPARATUS FOR MEASURINGHUMIDITY CONDITIONS IN MATERIALS Original Filed Nov. 3, 1948 2Sheets-Sheet 2 INVENTOR.

ATTORA/E Y United States Patent 50 APPARATUS FOR MEASURING HUMIDITYCONDITIONS IN MATERIALS Carlton E. @hiheiser, Silver Spring, Md,assignor to The American Instrument Company, Silver Spring, Md., acorporation of Maryland Original'application November 3, 1948, SerialNo. 58,146, now Patent No. 2,655,734, dated October 20, 1953. Dividedand this appiicaticn October 16, 1953, Serial No. 386,498

Claims. (Cl. 73-73) My invention relates broadly to humidity controlsystems, and more particularly to an apparatus for the precision controlof humidity in materials.

This application is a division of my application Serial Number 58,146filed November 3, 1948, for Method and Apparatus for ControllingHumidity Conditions in Bulk Materials, now Patent 2,655,734, datedOctober 20, 1953.

One of the objects of my invention is to provide an apparatus responsiveto conditions of humidity existent in material such as grain, soap,granular bromides, malt, and other confined and granular materials.

Another object of my invention is to provide control means formaintaining grain and other granular materials at proper conditions ofhumidity for preservation of the grain or granular material, and theprevention of spoilage thereof.

Another object of my invention is to provide an arrangement fordistributing humidity control devices throughout the area of granularbodies, for detecting changes in humidity conditions and automaticallycontrolling by such changes compensation means for maintenance of properconditions of humidity necessary to the preservation of the granularmaterial.

Still another object of my invention is to provide control meansoperative under conditions of changes in humidity in material foroperating forced draft equipment for blowing air through the materialfor compensating for undesirable conditions of humidity and restoringthe granular material to a proper humidity condition for the properpreservation thereof.

Other and further objects of my invention reside in an apparatus formaintaining granular material under conditions of substantially constanthumidity, as set forth more fully in the specification hereinafterfollowing, by reference to the accompanying drawings, in which:

Fig. l is a side elevational View of one of the humidity sensingelements employed in the system of my invention, the view beingparticularly broken away for indicating the individual sensing elements,employed in the system of my invention; Fig. 2 is a transverse sectionalview through the humidity sensing device taken substantially on line 2-2of Fig. 1; Fig. 3 illustrates the application of the humidity sensingdevice of my invention to a grain storage silo wherein a multiplicity ofthe humidity sensing devices of Figs. 1 and 2 are distributed throughoutthe area of the grain storage silo and become buried in the graintherein and serve as detectors of humidity conditions in the bulk grain;Fig. 4 is a transverse sectional view taken substantially on line 44 ofFig. 3; Fig. 5 is a schematic view illustrating the manner in which thehumidity sensing device controls the distribution of compensating airthrough the grain in the grain storage silo of Figs. 3 and 4; Fig. 6 isan enlarged elevational view of one of the detectors for controlling theflow of humidity compensating air through the grain storage silo; Fig. 7is a vertical sectional view taken substantially on line 7-7 of Fig. 6;and Fig. 8 is a 2,834,201 Patented May 13, 1958 detail view showing themechanization for controlling the position of the damper in the humiditycompensating system employed in the grain storage silo of Figs. 3 and 4.

Referring to the drawings in detail, reference character 1 designates asupporting head or device for a plurality of individual humidity sensingelements which I have designated at 2, 3, 3 and 5 supported by head 1.Individual humidity sensing elements are protected by a foraminatedcasing or guard 6 to which there is attached a conical shaped end orhood 7. The foraminated casing or guard 6 protects the humidity sensingelements 2, 3, 4, and 5 from direct contact with grain, molding sand,soap, bromide granular material or other granular material whileenabling the sensing elements to be thrust into the granular materialand buried therein by means of the conical shaped end or hood '7. Thehumidity sensing elements may thus be located within the granularmaterial in positions which will detect true humidity conditions thereinbecause the humidity sensing elements are sufiiciently spaced from theinside of the foraminated casing or guard 6 to enable the moisturepresent in the gases surrounding the material in which the device isinserted to circulate into contact with the humidity sensing elements.In Figs. 3 and 4 I have shown the application of my invention to theprotection of grain 8 stored in the grain storage silo 9. The grainstorage silo 9 includes a base support It) beneath which a forced draftor" air is induced from fan 11 to conduit 12 and directed upwardlythrough the central duct indicated at 14 and dis-charged through the airvents designated at 15 and 16 in the roof 17 of the silo 9. The grain 8is delivered to the silo 9 in conventional manner through a suitabledelivery conveyor tube 18 and is discharged in a similarly conventionalmanner through discharge opening 19. When the silo is not being filledthe conveyor tube 18 is closed off by a suitable valve not shown. Thegrain is divided into horizontal sectional areas throughout the entirevertical height of the silo and each of these areas is protected by ahumidity sensing element which is buried in the grain as represented at20, 21, 22, 23, 24 and 25 and at 26, 27, 28, 29, 30 and 31 in Fig. 3. inhorizontal plan view the distribution of these humidity sensing elementsis as set forth in Fig. 4 where two other columns of humidity sensingelements are buried in the grain at spaced intervals throughout theheight of the grain storage silo as represented by humidity sensingelements 32 and 33.

The electrical conductors leading from the humidity sensing elementsthrough the head 1 therein are brought out from each of the humiditysensing elements at the position 34 represented in Fig. l, and shownschematically in Fig. 3. The conductors leading from the sensingelements are carried to a control panel from which the operation of thesilo is regulated. Fig. 5 represents the equipment 'for each of thesensing control units on the control panel. The humidity sensing element23 electrically connects with the hygrometer equipment representedgenerally at 35 including an indicator schematically shown at .36 whichelectrically responds to the humidity sensing element 23. The indicator36 is supplied with power from the conventional volt power line which Ihave indicated as a source 37, power from which is con trolled bysensing element 23 to operate the pneumatic recorder controlier shownschematically at 38. The pneumatic recorder controller is also suppliedwith 115 volt power through power line connection 39. A constantpressure air line 48 connects with the pneumatic recorder controller 38and supplies the continuous pressure at approximately 17 p. s. i. Thispressure is controlled through the control pressure air line representedat 41 which eX- tends upwardly through the air duct 14- immediatelyadjacent the interior wall thereof leading tothe air pressure dampermotor schematically shown at 42. The air pressure damper motor 42 servesto control the movement of damper or valve 43 which normally closes theopening 44 in the side of the air duct 14 of the silo. Opening 44 isclosed by an open mesh screen 45 which permits passage of air currentswhen damper 43 is open but which prevents the loss of grain through thewall of the silo when the damper 43 is open.

Opening 44 is representative of similar openings at different horizontallevels throughout the silo. In the outer wall 60 of the silo openings 61are arranged at the same horizontal levels as openings 61 and covered byscreens 62 to prevent loss of the grain. The outer wall 60 is surroundedby the spaced jacket 63 forming an annular stack 64 around the silo forthe passage of air upwardly from the openings 61 to the air vents 15 and16.

The damper or valve 43 is hinged at the top thereof through hinges 46and normally gravitationally closes the opening 44. The lower edge ofdamper or valve 43 has a pair of lugs 47 thereon which are connectedthrough link 48 with plunger 49 of the air pressure damper mtor 42.Increase in air pressure in the controlled pressure air line 41 operatesair pressure damper motor 42 to angularly shift damper 43 to the dottedline position 43' illustrated in Fig. 7 restricting the flow of airthrough the duct 14 and diverting the air into substantially horizontalpaths through the bulk grain 8 thus directing the passage of aircurrents through the protected section of the silo which through theoperation of the humidity sensing element 23 calls for air forcompensating for an abnormal humidity condition.

The dampers 43 all open outwardly into the duct 14 from the top hingedconnections thereof with the interior wall of the duct 14 so that thedampers serve as defiectors for the upwardly moving air and skim off anddivert quantities of the air for distribution through the bulk grain 8.The arrangement of the openings '61 in the wall 60 of the silosubstantially horizontally aligned with the dampers 43 insure thepassage of the air in substantially horizontal paths through the bulkgrain 8 and the discharge of the air upwardly within the annular slack64 between the wall 60 and the jacket 63 surrounding the wall 60 inspaced relation thereto.

The several pressure air lines 41 extending from dampor motors 42 aregrouped around the side wall of the central air duct 14 and lead to theequipment shown in Fig. at the central control board. By dividing thesilo into horizontally localized areas as illustrated in Figs. 3 and 4,dangerous conditions of humidity which may develop in the protectedareas throughout the silo are promptly detected on the indicator 36 andthe condition recorded on the pneumatic recorder controller 38 andimmediately corrected by the supplying of compensating quantities of airby the opening of the individual damper or valve 43 controlled by theadjacent humidity sensing element.

Abnormal conditions of humidity which may occur in any area of the grainwithin the silo may produce a condition of spoilage which might spreadthroughout a large portion of the silo with a resulting loss of thegrain. However, by proper distribution of the humidity sensing elementsthroughout the grain, compensating dry air may be supplied over asuflicient time period at each of the danger zones to eliminate thedangerous condition of humidity before the grain can be appreciablyinjured.

I have found the apparatus of my invention highly practical in theprotection of materials and in the determination of the characteristicsthereof, and while I have described my invention in certain of itspreferred embodiments, I realize that modifications and changes may bemade, and I desire that it be understood that no limitations upon myinvention are intended other than may be imposed by the scope of theappended claims.

What I claim as newand desire to secure by Letters Patent of the UnitedStates is as follows:

1; Apparatus for measuring conditions of humidity in material comprisinga defice constituting a cylindrical hood structure insertable into thematerial for forming an air pocket therein, a support for a multiplicityof humidity sensing elements carried interiorly of said hood, amultiplicity of selectively removable and replaceable humidity sensingelements mounted on said support, said hood structure being perforatedto permit the moisture in the air surrounding the material in which thedevice is inserted to circulate in contact with the humidity sensingelements, electrical measuring apparatus, and connections from saidhumidity sensing elements through said support with said. electricalmeasuring apparatus for impressing upon said measuring apparatus controlcurrents integrated from each of said humidity sensing elements.

2. Apparatus for measuring conditions of humidity in material whichcomprises a device constituting a hood forming a pocketlike enclosure,penetrating means on the hood for eifecting a forceful entry into thematerial for determination of humidity conditions therein, a pluralityof electrical sockets disposed interiorly of one end of said hood,electrical humidity sensing elements independently mounted in saidsockets, said elements being selectively insertable into and replaceablewith respect to said sockets, said hood being perforated to permit themoisture in the air surrounding the material in which the device isinserted to circulate in contact with the humidity sensing elements,electrical connections from said sockets extending exteriorly of saidhood, and electrical current indicating means electrically connectedwith said connections for indicating changes in electrical conditionsdeveloping in said electrical humidity sensing elements due to changesin humidity arising in the material in which said hood is inserted.

3. Apparatus for measuring conditions of humidity in material comprisinga device having a flat circular base, a plurality of sockets arranged inspaced positions on said base, independent cylindrical humidity sensingelements removably mounted in said sockets and projecting on mutuallyparallel axes normal to said base to substantially the same lineardistance therefrom, said cylindrical humidity sensing elements beinglocated in spaced relation to each other for the circulation of gasestherearound, foraminated guard means carried by said base and encirclingall of said cylindrical humidity sensing elements and preventing contactbetween said elements and the material into which said guard means isthrust while allowing the moisture present in the gases surrounding thematerial in which the device is inserted to circulate into contact withthe humidity sensing elements, and electrical measuring apparatusconnected with said humidity sensing elements for measuring theintegrated response to the effect of changes in humidity in all of saidhumidity sensing elements.

4. Apparatus for measuring conditions of humidity in material comprisinga device having a circular base structure, means for securing electricalterminals on one side of said base, means for supporting a multiplicityof humidity sensing elements on the other side of said base in mutuallyspaced relation for the circulation of gases therebetween, said elementseach extending from said base for substantially the same linear distanceon .axes parallel to each other, foraminated guard means carried by saidbase andenclosing all of said humidity sensing elements in spacedrelation thereto for protecting said humidity sensing elements fromcontact with' material into which said guard means is thrust whileallowing the moisture present in the gases surroundingthe material inwhich the device is inserted to circulate into contact with the humiditysensing elements, and electrical connections extending from each of saidhumidity sensing elements to the electrical terminals on the exterior ofsaid base and electrical measuring apparatus connected with said 2,8 5terminals for measuring the integrated response to the effect of changesin humidity in all of said humidity sensing elements.

5. Apparatus for measuring conditions of humidity in material comprisinga flat circular base, a plurality of individual humidity sensingelements mounted on said base and projecting therefrom on lineal axessubstantially parallel one to the other and for substantially the samedistance from said base, said humidity sensing elements beingsufiiciently spaced for the circulation of gases therearound, acylindrical forarninated casing connected with said base and extendingon an axis normal thereto surrounding said humidity sensing elements andterminating at a position spaced from said base in a lateral planeapproximately in the plane of the terminating end of said humiditysensing elements, said foraminated casing being open at said terminatingend to permit the insertion and removal of the individual humiditysensing elements, a detachable cap closing the terminating end of saidforaminated casing, said humidity sensing elements being connectedthrough said base to connecting means attached to the exterior of saidbase, and electrical measuring apparatus connected to said connectingmeans for measuring the integrated response to the etfect of changes inhumidity in all of said humidity sensing elements.

References Cited in the file of this patent UNITED STATES PATENTS2,105,683 Burdick Jan. 18, 1938 2,342,553 Olpin Feb. 22, 1944 FOREIGNPATENTS 540,783 France Apr. 22, 1922 533,381 Great Britain Feb. 12, 1941

